Liquid light-guide catheter with optically diverging tip

ABSTRACT

A light-diverting catheter tip is provided according to embodiments disclosed herein. The light-diverting catheter tip may be coupled with the distal tip of a laser catheter and divert at least a portion of the light exiting the distal tip of the laser catheter such that the spot size of the laser beam on an object after exiting the catheter tip is larger than the spot size of the light entering the catheter without the catheter tip. The catheter tip may be removably coupled with the catheter or constructed as part of the catheter. In other embodiments, the catheter tip may conduct fluid and/or divert fluid at the tip of the laser catheter.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/254,254, filed Oct. 20, 2008, entitled “LIQUID LIGHT-GUIDECATHETER WITH OPTICALLY DIVERGING TIP,” now U.S. Pat. No. 9,421,065,issued on Aug. 23, 2016, which is a continuation-in-part of commonlyassigned U.S. patent application Ser. No. 12/176,886, filed Jul. 21,2008, entitled “Tapered Liquid Light Guide,” now U.S. Pat. No.8,979,828, issued on Mar. 17, 2015, and U.S. patent application Ser. No.12/061,430, filed Apr. 2, 2008, entitled “Laserwire With TaperedWaveguide,” now abandoned, the entirety of each of which is hereinincorporated by reference for all purposes.

BACKGROUND OF THE INVENTION

This disclosure relates in general to light guides and, but not by wayof limitation, to liquid light guides and/or catheters with diverging orconverging tips among other things.

Catheters containing optical fibers transmit energy to irradiateinternal parts of the body for diagnostic and therapeutic purposes.There are many medical applications in which it is desirable to deliverenergy, such as laser energy, through an optical fiber or similarwaveguide device disposed in a body cavity for treatment or diagnosis.These include, among others, the ablation of tissue such as fibrousplaque, thrombus, calcified plaque, and tumors, the destruction ofcalculi, and the heating of bleeding vessels for coagulation. Someablation targets, such as calcified endovascular lesions, for example,can be especially difficult to ablate. The lasers used may produceeither pulsed or continuous-wave light of wavelengths ranging from theultra-violet to the infra-red.

BRIEF SUMMARY OF THE INVENTION

Various catheters, catheter tips, fiber optics, and/or light guides areprovided according to embodiments disclosed herein. In variousembodiments, light guides and/or catheters may have tips with variousconfigurations that increase the energy density and/or increase the spotsize of the resulting beam of light. In some embodiments catheters areprovided that incorporate, for example, liquid light guides, fiberoptics with diverging tips, and/or fiber optics with converging tips.

A catheter tip is provided according to one embodiment. The catheter tipmay include a housing, and deflection member. The housing, for example,may be attachable to a laser catheter, and have an inner lumenconfigured to receive light traveling in a substantially uniformdirection from the laser catheter. The deflection member may bepositioned in the interior of the inner lumen, and include a proximalend, a distal end, and a tapered region. The distal end may have adiameter greater or smaller than the proximal end. The tapered region,for example, may extend from the proximal end to the distal end suchthat when the light contacts the tapered region, the light is divertedfrom its substantially uniform direction to produce a light pattern thatis larger or smaller than a light pattern produced without the lightdiversion. In some embodiments, the deflecting member is conical inshape.

In various embodiments, the interior of the deflecting member is hollowsuch that a portion of the light is capable of passing through thedeflecting member without being diverted. In some embodiments, the innerlumen is capable of receiving a liquid medium that flows in asubstantially uniform direction that facilitates light transmission. Thediverting member may be capable of diverting the liquid medium from thesubstantially uniform direction. In some embodiments, the divertingmember may include a linear or nonlinear tapered tip or tapered tipportion or tapered tip insert. In other embodiments the inner lumenand/or the deflecting member may be constructed from a material havingan index of refraction less than the liquid medium.

A catheter tip is also provided, having a housing, light-receiving meansand light-diverting means. The housing may be attachable with a lasercatheter and have an inner lumen with a central axis extending along thelongitudinal length of the inner lumen. The light-receiving means mayreceive light within the inner lumen such that the received lighttravels along the central axis of the inner lumen. The light-divertingmeans may divert the light from the direction along the central axisprior to exiting the catheter tip. The light-diverting means, forexample, may be located within the inner lumen. In some embodiments, thehousing has an outer diameter and the light exiting the tip produces aspot size on an object in close proximity to the catheter tip that has adiameter at least the same size as the outer diameter of the housing. Insome embodiments, the light-diverting means may include a tapered tip ora tapered tip portion or a tapered tip insert.

A laser catheter is provided according to another embodiment. The lasercatheter may include a proximal end, a distal end, an inner lumen, aplurality of fibers, an infusion port and a deflecting member. The innerlumen may include a central axis extending from the proximal end towardthe distal end. The plurality of fibers may be configured to transmitlight received at the proximal end toward the distal end. The pluralityof fibers may be positioned within the inner lumen of the lasercatheter. The infusion port may be configured to receive a liquid andproduce a flow of the liquid through the inner lumen toward the distalend substantially along the central axis of the inner lumen. Thedeflecting member may be positioned within the inner lumen near thedistal end. The deflecting member may be capable of diverting at least aportion of the fluid from exiting the inner lumen at the distal end fromsubstantially along the central axis of the inner lumen.

A catheter tip is also provided according to another embodiment. Thecatheter tip may include a housing and a deflection member. The housingmay be operable with a laser catheter and include an inner lumenconfigured to receive light emitted by the laser catheter. The emittedlight may have a first diameter corresponding to an inner diameter ofthe laser catheter, and the light travels in a substantially uniformdirection along the longitudinal length of the inner lumen. Thedeflecting member may be positioned within the housing. The deflectingmember may have a proximal end and a distal end with a tapered regiontherebetween. The deflecting member may function to divert the receivedlight from the uniform direction such that the light exiting thecatheter tip has a second diameter which is larger than the firstdiameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a laser catheter system according to one embodiment.

FIGS. 2A, 2B, 2C, and 2D show examples of tapered waveguides accordingto one embodiment.

FIG. 3 shows a laser catheter according to another embodiment.

FIG. 4 shows a cross-section of a laser catheter according to anotherembodiment.

FIG. 5 shows a cross-section of the distal end of a laser catheter witha tapered end according to another embodiment.

FIG. 6A shows a bundle of untapered waveguides covering a laser lightprofile according to another embodiment.

FIG. 6B shows a bundle of tapered waveguides covering a laser lightprofile according to another embodiment.

FIGS. 7A, 7B and 7C show cross-sections of tapered waveguides accordingto various embodiments.

FIGS. 8A and 8B show waveguides with proximal cylindrical ends accordingto another embodiment.

FIGS. 9A and 9B show various views of a waveguide with a proximalcylindrical end and a distal cylindrical end according to anotherembodiment.

FIG. 10 shows a tapered liquid light guide tip according to oneembodiment.

FIG. 11 shows a tapered liquid light guide tip coupled with a lasercatheter according to one embodiment.

FIG. 12 shows a laser catheter coupled with a tapered liquid light guidetip according to one embodiment.

FIGS. 13A-13C show tapered liquid light guide tips with variousattachment mechanisms according to various embodiments.

FIG. 14 shows a tapered liquid light guide sheath according to oneembodiment.

FIG. 15A shows an example of the distal end of a laser catheterincorporating a liquid light guide according to one embodiment.

FIG. 15B shows an example of a laser spot size using the laser cathetershown in FIG. 15A.

FIG. 16A shows an example of the distal end of a laser catheterincorporating a liquid light guide and diverting cone according to oneembodiment.

FIG. 16B shows an example of a laser spot size using the laser cathetershown in FIG. 16A.

FIGS. 17A, B, and C show the distal end of a laser catheter withdifferent shaped diverting cones according to some embodiments.

FIG. 18 shows a portion of a catheter incorporating a diverting coneaccording to one embodiment.

FIGS. 19A, B, and C show various examples of placement of the divertingtip within the distal end of a catheter according to some embodiments.

FIGS. 20A, B, C, D, and E show various diverting cone configurationsaccording to various embodiments.

FIGS. 21A, B, and C show various attachment mechanisms for coupling adiverting cone with a fiber optic according to various embodiments.

FIGS. 22 shows a detachable tip apparatus with a diverting cone that canbe coupled with the distal end of a laser catheter according to someembodiments.

FIGS. 23A and B show attachment mechanisms for a diverting cone within alaser catheter according to one embodiment.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

DETAILED DESCRIPTION

The ensuing description provides preferred embodiment(s) only, and isnot intended to limit the scope, applicability or configuration of thedisclosure. Rather, the ensuing description of the preferredembodiment(s) will provide those skilled in the art with an enablingdescription for implementing a preferred embodiment. It should beunderstood that various changes may be made in the function andarrangement of elements without departing from the spirit and scope asset forth in the appended claims.

Various embodiments are described throughout this disclosure. Thevarious embodiments share a number of themes. For example, embodimentslargely describe catheters and/or removable catheter tips that may haveuniquely configured tips. For example, the distal tip may include ataper with a distal tip larger than the catheter body, a taper with adistal tip smaller than the catheter body, diverting tips, and/or fiberoptics within a catheter with such configurations. Moreover, embodimentsdescribed herein may be used in a variety of catheters, for example,laser catheters, liquid catheters, etc. Other embodiments may be used inwaveguides.

At least three major embodiments are described in detail with furtherdescriptions of a variety of sub embodiments. These embodiments includetapered waveguides with a portion of the catheter having a tip with alarger cross section than the catheter body. Embodiments also includetapered catheters with a smaller distal tip cross section than thecatheter body. Embodiments may also include liquid catheters withdiverting tips. Each of these three embodiments along with varioussub-embodiments and/or features are described in detail within thefollowing three sections.

I. Tapered Waveguide Concept

In one embodiment, the present disclosure provides for taperedwaveguides. According to embodiments described in this disclosure,tapered waveguides have at least one end with a circumference largerthan the circumference of the waveguide body. Such waveguides provideincreased exit and entrance apertures. An increased entrance aperturewith respect to the waveguide body, for example, may provide anincreased coupling cross-section, while maintaining a flexible waveguidebody. An increased exit aperture with respect to the waveguide body, forexample, may provide an increased cutting cross-section for lasercatheter applications, while maintaining a flexible waveguide body. Forexample, a proximal end may have a circumference greater than thewaveguide body, the distal end may have a circumference greater than thewaveguide body, or both the distal and proximal end may have acircumference larger than the waveguide body. The taper betweencircumferences may be gradual of abrupt. An abrupt taper, for example,may have, for example, an infinite slope. A more gradual taper, forexample, may taper between the two circumferences over a couplemillimeters or up to a couple meters. A tapered waveguide may be alaserwire, fiber optic, hollow waveguide, etc. The slope of a taper isdirectly proportional to the amount of light lost in the taper. Forexample, a gradual taper provides less loss than a quicker taper.

In another embodiment, the present disclosure provides for a lasercatheter comprising one or more tapered waveguides. Such a catheter maybe coupled with a laser or other light source and be configured todirect light through the one or more waveguides toward a target within,for example, a human body. One or more tapered waveguides with aproximal end circumference larger than the waveguide body, according toembodiments, may provide increased coupling with the light source. Insuch embodiments, each waveguide may capture more light at the laserinterface. One or more tapered waveguides with a distal endcircumference larger than the waveguide body, according to embodiments,may provide a cutting cross-section, which lends itself to increaseablation energy. Use of tapered waveguides may allow for more flexiblecatheters. In some embodiments, a single tapered waveguide may be usedwithin a catheter.

FIG. 1 shows a laser catheter system 100 according to one embodiment. Alaser 130 is shown coupled with a user interface 180. In this embodimentthe user interface 180 is computer programmed to control the laser 130.The laser, for example, may be an excimer laser. The laser, for example,may also produce light in the ultraviolet range. The laser is connectedwith a catheter 170 that may be inserted into a vessel of the human body110. The laser catheter system 100 may employ one or more taperedwaveguides that guide laser light from the laser 130 through thecatheter 170 toward a target.

FIGS. 2A, 2B, 2C, and 2D show examples of tapered waveguides 205, 206,207, 208 according to various embodiments. These tapered waveguides 205,206, 207, 208 may be used, for example, within the catheter 170 shown inFIG. 1. The tapered waveguide 205 shown in FIG. 2A includes a waveguidebody 210, a proximal tapered waveguide end 220A, and a distal taperedwaveguide end 220B. Light from a light source, such as a laser, may bereceived at the surface 221 of the proximal tapered waveguide end 220Aand is transmitted through the waveguide body 210. The proximal taperedwaveguide end is tapered from a first circumference or diameter at thejunction with the waveguide body at the surface 221 of the proximaltapered waveguide end 220A to a second circumference or diameter.

FIG. 2B shows a waveguide 206 with only a proximal waveguide end 220A.FIG. 2C shows a tapered waveguide 207 with an extended end portion 225with the proximal waveguide end 220A. FIG. 2D shows a tapered waveguide208 with a gradual taper 265.

Generally speaking, tapered waveguides have not been considered a viableoption because of light loss within the tapered portion of thewaveguide. Waveguides take advantage of total internal reflection toguide light from the proximal end of a waveguide toward the distal endof the waveguide. Light within the waveguide that is incident on thewalls of the waveguide at an angle less than the critical angle isinternally reflected. The angle may be managed to minimize reflectionlosses by geometric design and by the choices of optical materials. Thecritical angle is defined by the materials used at the interface of thewaveguide and the exterior of the waveguide. Materials are usuallyselected tor waveguides that ensure the light within the waveguide isinternally reflected to move the light through the waveguide. Lightincident on a taper in the waveguide, going from a larger circumferenceor diameter to a smaller circumference or diameter, may be incident onthe outer surface of the waveguide at an angle less than the criticalangle. The critical angle is affected by the step function in the indexof refraction at the boundary of the light guide medium and theconfining medium. Accordingly, such light will not be internallyreflected and will be lost. This loss, due to the taper, has discourageduse of tapers in waveguides. However, according to embodiments providedin this disclosure, the loss effected by such a taper may be less thantosses associated with a small waveguide cross-section. Moreover, atapered waveguide may also be less complicated than other options.

The waveguides may comprise any dimension. For example, the length 250of the waveguides may be three to four meters according to oneembodiment. The diameter 240 of the proximal tapered waveguide end maybe 150 microns and the diameter 241 of the distal tapered waveguide endmay also be about 150 microns. In other embodiments the diameter of eachtapered waveguide end may be different. As another example, depending onthe application, these diameters 240, 241 may range from 50 microns toover 1,000 microns. The waveguide body 210 may have a diameter, forexample, ranging from 40 microns to 600 microns. Various otherdimensions may be used without limitation. As another example, the taperdimensions 245, 246 may extend from less than 1 mm to over 5 mm. Inother examples, the taper may extend over 1 meter or longer and may beas little as 10 microns. In some applications the waveguide body may beflexible.

A tapered waveguide may comprise dielectric material with highpermittivity and/or index of refraction. The waveguide may be surroundedby cladding with low permittivity and/or index of refraction. Such awaveguide, for example, an optical fiber, guides optical wavestherethrough by total internal reflection. Other types of opticalwaveguides may be such as, for, a photonic-crystal fiber, a hollow tubewith a highly reflective inner surface, light pipes. A hollow waveguidemay include internal surfaces covered with a polished metal or coveredwith a multilayer film that guides light by Bragg reflection. An opticalfiber waveguide, for example, may comprise plastic, silica, or any otherglass. In some applications, such as when used with an ultraviolet lightsource, the optical fibers may have a high OH or high saline material.

The optical waveguide may comprise material that is well matched to thetype of light it guides. For example, an ultraviolet waveguide may becomprised of material that is transmissive to ultraviolet light. Forexample, the waveguide may be an optical fiber with a high OH or salinecontent. As another example, an infrared waveguide may have a low OHcontent. According to another embodiment, the waveguide may aim compriseplastics, quartz, and/or sapphire. The waveguide may, for example, becylindrically shaped or may comprise an elongated shape with an oval,square, hexagonal, octagonal, triangular, etc cross section. Accordingto another embodiment, the waveguide may be hollow. In yet anotherembodiment, the waveguide may comprise multiple geometries that varyover the length of the waveguide.

FIG. 3 shows a laser catheter 300 according to another embodiment.According to this embodiment, the laser catheter 300 includes a lasercoupler 310 that may be coupled with a laser (as shown in FIG. 1). Thelaser catheter 300 includes a tail tube 315 and torque handle 330. Thetorque handle 330 may be used to rotate the catheter body in order tosteer within discrete locations of the body vasculature. The catheterbody portion may include an internal lumen for introduction over aguidewire. The hypotube 320 construction, for example, may providesufficient torque, stiffness and pushability to the catheter 300 insituations where it is not configured to be introduced over a guidewire.The distal end 340 of the catheter may include a flexible distalsection. The hypotube, for example, may be 180 to 300 cm in length andhave a diameter of about 0.014 inches.

The distal end 340 may include any of the waveguides described inassociation with embodiments presented in this disclosure. The taperedwaveguide may have a tapered distal and-or proximal section as describedin any of the embodiments of the invention. Moreover, the distal end 340may include a waveguide with large cylindrical distal ends and/orproximal ends as will be described in association with FIGS. 8A, 8B, 9Aand 9B. A waveguide may extend through the hypotube 320 and tail tube315. Accordingly, the proximal end of the waveguide may be coupled withthe laser coupler 310. The proximal end of the waveguide may also beconfigured to receive laser light at the laser coupler 310 when thelaser catheter is coupled with a laser. A larger cross-section at theproximal end of a waveguide may provide, for example, a larger laserlight-collecting surface area at the laser coupler 310. In yet otherembodiments, for example, like those shown in FIGS. 16-20, the distalend may include a tapered tip or a tapered portion or a tapered insertthat diverges light outwardly from the catheter diameter.

In some embodiments a taper in the waveguide may occur within the tailtube 315, torque handle 330, laser coupler 310, and/or a combinationthereof. In some embodiments, a taper from a larger circumference ordiameter waveguide to a smaller circumference or diameter waveguidegradually occurs throughout the portions or the entire tail tube 315. Inother embodiments, a taper may occur less gradually, for example, withinthe laser coupler 310, or the torque handle 330. In yet otherembodiments, a taper may occur within the hypotube 320. Various otherembodiments may envision tapers within other portions of a waveguidewithout limitation.

A cross-section of the flexible distal section 340 cut along section A-Aof FIG. 3 is shown in FIG. 4 according to one embodiment. As shown, awaveguide core 405 is surrounded by the hypotube 410. The hypotube 410may be adhered to the waveguide core 405 with epoxy 415. The waveguidecore 410 may comprise one optical fiber or a plurality of optical fibersbundled together. Various other waveguides may be used within theoptical core of the laser catheter, for example, hollow waveguides,multiple core waveguides, etc.

FIG. 5 shows another cross-section of the distal end of the lasercatheter 300 cut along section B-B of FIG. 3, according to oneembodiment. A tapered waveguide 405 is shown surrounded by epoxy 415 anda hypotube 410. According to another embodiment, the distal end of thelaser catheter 300 may include a radiopaque coil 530 or marker band. Thecoilband 530 or marker band of various shapes and sizes may be comprisedof a radiopaque material such as platinum-indium or other suitablematerial and may be disposed near the distal tip of the catheter to aidin fluoroscopic or other visualization of the placement of distal tip.In some embodiments, the hypotube may also include a shape ribbon 540.The shape ribbon, for example, may have a constant width. In someembodiments, the ribbon of material may have a width that continuouslyand/or smoothly increases toward the proximal end of the hypotube. Insome embodiments, the ribbon may have discrete sections where the widthof each successive section is larger than the width of the adjacentdistal section.

In some embodiments of the invention a plurality of tapered waveguidesmay be used to direct laser light from the proximal end to the distalend of a laser catheter. FIG. 6A shows a cross-section of a plurality ofwaveguides without tapered ends 610A packed within a laser profile 605.A laser profile may have a fixed profile as shown in the figure. In thisexample, the laser profile 605 has a fixed profile of about 1 mm by 1.5mm. In this example, 67 waveguides are packaged within a laser catheter.The number of waveguides used within a single catheter may be limited bythe various design constraints such as, for example, desired flexibilityof the laser catheter, the circumference or diameter of each waveguide,the required energy output, etc. In the example shown in FIG. 6A, the 67waveguides with diameters of approximately 50 microns to meet thedesired design constraints of the laser catheter.

As shown, such waveguide cross-sections and the number of waveguidescover less than half of the laser profile 605. Accordingly, more thanhalf the laser energy is lost prior to entry at the waveguides. Thenumber of waveguides could be increased to capture more laser energy,but such an increase would limit the flexibility of the laser catheter.Moreover, focusing of the laser light from the full profile to a profilefocused on a smaller profile using optical elements may be used, but anyoptical element is inefficient and introduces losses in the laserenergy. Tapered waveguides, as described in embodiments of thisdisclosure, may be used to collect more laser energy by increasing thewaveguide cross-section at the proximal end of the waveguide, as shownin FIG. 6B, without sacrificing flexibility throughout the lasercatheter body. Moreover, in another embodiment of the invention, a taperat the distal end of a waveguide may be used, with or without a proximaltaper, to increase the cutting cross-section area of the distal end ofthe waveguide without interfering with the tractability of the lasercatheter. While the packing configurations shown in FIGS. 6A and 6B arerectangular, the packing configuration is not limited thereby. Thepacking configuration may be round, hexagonal, or scattered depending onsuch things as the catheter and/or laser profile cross sections.

FIGS. 7A, 7B and 7C show cross-sections of tapered waveguides accordingto various embodiments. FIG. 7A shows a waveguide with a waveguide body210 and a tapered end 220. The waveguide has a hypotube 710 surroundingthe waveguide and coupled with the waveguide using epoxy 705. In FIG. 7Athe hypotube 710 diameter is the same as the diameter of the largestpart of the tapered end 220. Thus, the waveguide tapers to the samediameter of the hypotube 710.

In FIG. 7B the hypotube 710 diameter is less than the diameter of thelargest part of the tapered end 220. Thus, the waveguide tapers to adiameter larger than the diameter of the hypotube 710. In FIG. 7C thehypotube 710 diameter is greater than the diameter of the largest partof the tapered end 220. Thus, the waveguide tapers to a diameter smallerthan the diameter of the hypotube 710.

FIG. 8A shows a waveguide 800 with a proximal cylindrical end 805attached with a waveguide body 810 according to another embodiment. FIG.8B shows a three dimensional view of a waveguide with a proximalcylindrical end 805. The cylinder may be comprised of waveguide materialwith a larger diameter, such as a larger diameter fiber. As shown, oneway to construct such a waveguide is to fabricate a hole 815 within acylinder that is dimensioned to securely receive the waveguide body 810.The hole 815 may be fabricated, for example, during production of thecylinder, or by drilling, or any other means. Glue, such as epoxy, maybe used to secure the waveguide body 810 with the cylinder 805. Aproximal cylinder end 805 may increase the cutting end of the waveguidesimilar to using a tapered proximal end. The cylinder 805 may, accordingto another embodiment, incorporate a tapered light-guide.

FIG. 9A shows a waveguide with a proximal cylindrical end 920 and adistal cylindrical end 805 according to another embodiment. The proximalcylindrical end 920 may be used to increase the energy captured from alaser. The most proximal surface 930 may be coated with a material thatpermits exterior light to enter the proximal cylindrical end 920. Themore distal surface 940 may be coated with a reflective surface. Thus,light entering the proximal cylindrical end 920 may only exit thecylinder through the waveguide body 810. Light may reflect back andforth within the proximal cylindrical end 920 until the light enters thewaveguide body 810. The cylinder 805 may according to anotherembodiment, incorporate a tapered light-guide.

FIG. 9B shows another waveguide with a proximal cylindrical end 920 anda distal cylindrical end 805 according to another embodiment. In thisembodiment, the more distal surface 945 of the proximal cylindrical endis concave and reflective. This surface focuses the light toward themore proximal surface 935, which may, according to one embodiment, becoaled with a material that permits exterior light to enter the proximalcylindrical end 920 but reflects light that is incident from within thecylindrical end 920. In another embodiment, the more proximal surface935 may include a single reflective portion located near the area wherelight may be focused by the concave more distal surface 945. Thus,according to this embodiment, light entering the more proximal surface935 is reflected and/or focused by the more distal surface 945 and thenreflected and/or focused through the waveguide body 810 by the moreproximal surface 935. A concave surface may be used on either the distalor proximal ends of the waveguide.

II. Tapered Catheter Tip

Embodiments described throughout this disclosure provide for tips,sheaths, catheters, and/or devices that increase the energy density of alaser catheter. Some embodiments use tapered liquid light guides thatdecrease the beam cross-section of laser light in order to increase theenergy density. Such energy density increases may be useful for ablatingstubborn lesions, occlusions, obstructions, etc. Moreover, many of theembodiments are directed to devices that may be accessories to astandard laser catheter. For example, various embodiments includedetachable and/or replaceable catheter tips and/or sheaths.

A tapered catheter tip is provided according to one embodiment. Such atapered catheter tip may be coupled with a laser catheter. The taperprovides a decrease in the laser spot size and, therefore, an increasein the energy density of laser light. Such tips, in one embodiment, maybe constructed of material with an index of refraction which is lowerthan the liquid medium on the inner lumen at the tip in order to induceinternal reflection from within the liquid core. In another embodiment,a tip may be constructed of a material that provides low lightattenuation. In some embodiments the laser catheter may provide light inthe ultraviolet range. Moreover, the tapered catheter tip may direct aliquid medium from the proximal end of the tip toward the distal end ofthe tip.

In use, a user may be performing laser ablation within a patient using aliquid light guide laser catheter. In this example, the laser cathetermay operate with 308 nm UVB light and the laser catheter may use a rangeof solutions such as NaCl solution as the liquid light guide medium. Atsome point in the procedure the physician may encounter a target that isdifficult to ablate with the laser catheter, such as calcifiedendovascular lesions. In such a case, an increased laser density mayprovide belter ablation. Accordingly, the physician may remove the lasercatheter, and attach a tapered catheter tip. The tapered catheter tipnarrows the spot size of the laser light emanating from the lasercatheter while transmitting roughly the same laser energy. The physicianmay then reinsert the laser catheter and ablate the difficult targetusing the tapered tip. Following ablation, the physician may remove thetip or continue ablation with the tapered tip.

Some embodiments provide a tapered catheter sheath. Such a cathetersheath may be an elongated tubular structure that accepts a lasercatheter through much of the elongated portion thereof. In otherembodiments the elongated tubular structure accepts a laser catheterthrough all, most of all, or a portion thereof. In some embodiments thecatheter sheath is tapered at the distal end to decrease the spot sizeof the laser light. In other embodiments the catheter sheath may includean infusion port that provides biocompatible fluid delivery through thesheath toward the distal end of the sheath. In another embodiment, asheath may be constructed of a material that provides low attenuation oflight. In some embodiments the sheath or at least a tapered portion ofthe sheath may be constructed of material with a low index of refractionin order to induce total internal reflection. In some embodiments thelaser catheter may provide light in the ultraviolet range.

FIG. 10 shows a tapered liquid light guide tip 1000 according to oneembodiment. The liquid light guide Up 1000 includes a distal end 1030and a proximal end 1020. In this embodiment both the distal end 1030 andthe proximal end 1020 include apertures. As shown in the figure the tipincludes a tapered portion 1010 between the proximal end 1020 and thedistal end 1030. In some embodiments, the proximal end 1020 of thetapered liquid light guide tip may be coupled with a laser catheter, aliquid light guide, or both.

FIG. 11 shows the proximal end 1020 of a tapered liquid light guide tip1000 coupled with a laser catheter 170 according to one embodiment. Onlya portion of the laser catheter 170 is shown. When coupled with a lasercatheter 170, the liquid light guide tip 1000 may direct laser lightwith a more concentrated spot beam toward a target from the distal end1030. In doing so, the energy density of the light incident on a targetfrom the laser catheter 170 through the liquid light guide tip 1000 isincreased due to the decrease in spot size. The laser catheter 170 mayalso provide a biocompatible fluid that flows through the liquid lightguide tip 1000 from the proximal end 1020 toward the distal end 1030. Inorder to decrease the spot size of the laser beam through the tip, totalinternal reflection must be maintained through the taper 1010 of theliquid light guide tip 1000. Total internal reflection can be maintainedwhen the biocompatible fluid has an index of refraction greater than theindex of refraction of the lining of the tubing.

The biocompatible fluid, in some embodiments, may include a salinesolution. In other embodiments the biocompatible fluid may includeMgCl₂, NaCl, CaCl, etc. In other embodiments the biocompatible fluid mayinclude a solution comprising, for example, Ca, Mg, Mn, Ni, Cl, and/orCo. In some embodiments, the biocompatible fluid may include lactatedRinger's solution. The lactated Ringer's solution, for example, may comefrom sodium chloride (NaCl), sodium lactate (NaC₃H₅O₃), calcium chloride(CaCl₂), and/or potassium chloride (KCl). Those of skill in the art willrecognize that other combinations of salts may be used. In someembodiments, magnesium chloride and lactated Ringer's solution have goodbiocompatibility (e.g., low toxicity) as well as good light transmissioncharacteristics at the 308 nm wavelength. The biocompatible fluid may betailored to the wavelength of light produced by the laser. For example,waveguides including a biocompatible fluid of approximately 15% toapproximately 60% by weight CaCl₂ transmit light well in the infrared,but only partially in the ultraviolet region. There are many types ofbiocompatible fluids that may be used without limitation. Moreover,embodiments described herein are not limited to specific biocompatiblefluid.

The body and/or walls of the tapered liquid light guide tip 1000 maycomprise any low index material without limitation. For example, amaterial with an index or refraction below the index of refraction ofwater, approximately 1.4 at the 308 nm wavelength. These materials mayinclude, for example, Teflon AF2400 tubing made by DuPont. In otherembodiments, the walls may include any fluoropolymer, such as, forexample, Hyflon® PFA or MFA, FEP, KEL-F, Teflon PFA, Tefzel, Fluon,Tedlar, ECTFE, PVDF, PCTFE, FFKM, Kalrez, Viton, Krytox, and 3M THV-500.Polyethylene, PVC, polycarbonate and/or other plastics may be used insome embodiments.

The tapered liquid light guide tip 1000 may include portions without ataper. For example, as shown in FIG. 10, the tip 1000 may include anextended portion 1050 near the proximal end and/or a extended portion1040 near the distal end. While the extended portion 1050 and/or thedistal aperture are shown with a circular cross section, any shape maybe used. For example, the cross section may be oval or polygon shaped.Moreover, in another embodiment, the distal end may taper directly tothe distal aperture 1030 without a substantially extended portion. Inanother embodiment, the tip may be substantially cone shaped. In such anembodiment, the tip may have substantially no extended portions.

FIG. 12 shows a laser catheter 1210 coupled with a tapered liquid lightguide tip 1000 according to one embodiment. The laser catheter 1210 alsoincludes an infusion port 1220 for introducing a biocompatible materialinto the laser catheter 1210. The biocompatible material may act as alight guide within the laser catheter that channels light from theproximal end through the liquid toward the distal end. The taperedliquid light guide tip 1000 includes a tapered portion 1010.

FIGS. 13A-13C show tapered liquid light guide tips with variousattachment mechanisms according to various embodiments. FIG. 13A showsan attachment mechanism such that a ring 1310 on the inside of the tipcatches a groove on the catheter according to one embodiment. In someembodiments, at least a portion or all of the attachment mechanismcomprises a shape-memory material that shrinks when heated to about thebody temperature. Shrinking may more lightly secure the tip to the lasercatheter when used within a body. In FIG. 13B a ring 1320 is on theexterior of the laser catheter and the groove is on the interior of thetip 1000 according to another embodiment. FIG. 13C shows the tip withthreads 1340 on the interior and the laser catheter with threads 1330 onthe exterior. Of course, the threads may be on the exterior of the tipand the interior of the laser catheter according to another embodiment.Various other attachment mechanisms may also be used without deviatingfrom the spirit and scope of this disclosure. For example, clips,detents, rings, washers, pins, bushings, o-rings, etc., may be used aspart of the attachment mechanism. In some embodiments, the taperedliquid light guide tip may be attached using an X-Ray contrast medium, asticky material or any adhesive.

FIG. 14 shows a tapered liquid light guide sheath 1400 according toanother embodiment. The liquid light guide sheath 1400 may include anelongated tubular body 1410, a tapered portion 1415, a distal aperture,an inner lumen, and an infusion port 1220. The infusion port 1220includes a catheter port 1460 that receives a laser catheter 170 orother light channeling device. The catheter port is configured to allowa catheter, such as a laser catheter, to be fed into the inner lumen ofthe sheath 1400. The sheath 1400 may also include a fluid port 1470 thatmay be coupled, for example, with a biocompatible fluid delivery device.The fluid port 1470 may receive biocompatible fluid that flows throughthe inner lumen of the sheath 1400. The biocompatible fluid may be usedas a light guide within portions of the sheath. In some embodiments, theliquid light guide sheath may include a distal extended portion 1420,while in other embodiments the sheath tapers substantially directly tothe distal aperture.

The tapered liquid light guide sheath 1400 may be used to direct laserlight from a catheter and biocompatible fluid toward a target. The lasercatheter 170 may slide within the inner lumen from the infusion port1220 toward the distal end. Portions of the sheath 1400 may act as aliquid light guide directing light from the laser catheter through adistal aperture toward a target. Accordingly, in some embodiments,portions of the tapered liquid light guide sheath 1400 may comprise alow index material and/or a low attenuation material. The type ofmaterial chosen as well as the type of biocompatible fluid used withinthe light guide may be chosen based on the wavelength of light producedby the laser catheter.

III. Diverting Catheter Tip

Embodiments described herein also provide for diverting catheter tips.These diverting catheter tips may be provided in a number ofcombinations. For example, the diverting catheter tips may includediverting tip attachments that can be coupled with the distal end of acatheter. As another example, diverting catheter tips may also beintegral with the distal tip of a catheter. Such diverting catheter tipsmay be used with liquid catheters and may divert the liquid as it exitsthe distal end of the catheter. Liquid catheters, in some embodiments,use a liquid medium as part of a light guide to transmit light throughat least a portion of the catheter toward the distal end of thecatheter. Diverting catheter tips expand the exit diameter of the distalcatheter tip and, in some embodiments, may provide an increased spotsize. Increasing the spot size of emitted laser light may be useful forcreating ablations substantially the same size or larger than the outerdiameter of the laser catheter.

FIG. 15A shows an example of the distal end of a laser catheter 1500incorporating a liquid light guide according to one embodiment. Suchcatheters may include a sheath 1510 having an inner lumen 1515 housing afiber-optic bundle 1520 capable of transmitting light. The fiber-opticbundle 1520, in some embodiments, may be arranged to terminate short ofthe catheter's tip such that a hollow portion 1540 is formed toward thecatheter's tip. In some embodiments, a liquid medium may be used as alight guide in conjunction with the fiber optic bundle. For example, abiocompatible liquid may flow through the catheter out the distal end ofthe catheter. The liquid may transmit light from at least the distalends of the fiber optic bundle through the hollow portion 1540 of thecatheter tip to facilitate in light transmission. The liquid medium mayhave an index of refraction greater than the inner lumen of the lasercatheter in order to induce total internal reflection as light travelsthrough the distal tip. In addition, the liquid medium may also have alow attenuation for UV light. The liquid medium may flow through thelaser catheter between the fibers of the fiber-optic bundle and fill thehollow portion 1540 of laser catheter 1500 and flow toward the distalaperture. The internal reflection of the light within the inner lumenacts to channel the light along the central axis 1505 of the inner lumen1515. Upon exiting the laser catheter, light generally continues along apath substantially parallel with the distal tip.

FIG. 15B shows an example of a laser spot size 1560 using the lasercatheter shown in FIG. 15A. As shown the spot size 1560 is smaller thanthe outside diameter 1565 of the laser catheter. The catheter shown inFIG. 15A may be used to ablate obstructions. Such ablations, however,will conform largely to the spot size 1560. However, even with such anablation, the laser catheter may not proceed through the ablationbecause the diameter of the catheter is larger than the ablation.

FIG. 16A shows an example of the distal end of a laser catheter 1600incorporating a liquid light guide and diverting tip 1650 according toone embodiment. The laser catheter 1600 is shown having a sheath 1610,an inner lumen 1615, a fiber-optic bundle 1620, a central optical fiber1630, a hollow portion 1640, and a diverting tip 1650 coupled with thecentral optical fiber 1630. In some embodiments, the fiber-optic bundle1620 terminates short of the catheter tip. In some embodiments, thefiber optic bundle terminates approximately 5 cm short of the tip. Inother embodiments, the fiber optic bundle terminates, less than, forexample, 1 cm, 2 cm, 3 cm, 4 cm, 6 cm, 7 cm, 8 cm 9 cm or 10 cm from thetip.

The laser catheter 1600 may partially or completely use a liquid mediumas light guide. The figures show catheters that partially use liquid asa light guide. However, catheters may also use a liquid light guidewithout fiber optics. As shown in the figures, the liquid medium may beintroduced within the catheter and travel between the fibers within thefiber optic bundle 1620 and fill the hollow space between the tip andfiber optic bundle. Light may be conducted along the way. The liquid, asit flows through the catheter, acts as a light guide directing lighttoward the distal end of the catheter. The liquid medium may include anybiocompatible solution, such as NaCl. In some embodiments, the liquidmedium may have a low attenuation for UV light, such as light emittedfrom an Excimer laser. The laser catheter 1600 is further shown having adiverting tip 1650 coupled with central optical fiber 1630. Sheath 1610and diverting tip 1650 may be made from the same material to induceinternal reflection within the inner lumen. For example, in someembodiments, these materials may include Teflon AF2400 tubing made byDuPont. In other embodiments, the materials may include anyfluoropolymer, such as, for example, Hyflon® PFA or MFA, FEP, KEL-F,Teflon PFA, Tefzel, Fluon, Tedlar, ECTFE, PVDF, PCTFE, FFKM, Kalrez,Viton, Krytox, and 3M THV-500, polyethylene, PVC, polycarbonate and/orother plastics.

As shown, the diverting tip 1650 may have a proximal end 1653 that issmaller in diameter than the distal end 1653 with a tapered region 1655extending therebetween. The proximal end 1651 may be fitted and/orsecured with a central optical fiber 1630. In other embodiments thediverting tip 1650 may be integral or part of the central optical fiber1630. In some embodiments, the diverting tip 1650 may be permanently orremovably attached to the central optical fiber 1630. In otherembodiments, the diverting tip 1650 may be positioned within the innerlumen 1615 so that the diverting tip intersects at least a portion ofthe flow of the liquid from the inner lumen. In such a position, withminimal light loss, the tapered region 1655 acts to divert/deflectliquid and/or light that contacts the tapered region from a pathcorresponding with the inner lumen's central axis 1605.

Using the liquid light guide with a diverting tip shown in FIG. 16Aprovides light outside the inner lumen diameter, and produces a largerspot size 1560 as shown in FIG. 16B. The diversion of the light resultsin a larger laser spot size 1560 and a corresponding ablation diameter.For example, the ablation diameter and/or spot size 1560 may be almostas large, as large as, or larger than the diameter of the catheter. Thelarger diameter ablation may form a more substantial opening that may,for example, encourage passage of the laser catheter through anobstruction. In some embodiments, the diverting tip 1650 may beconically shaped and produces a diverging light cone that isdiverted/deflected off the conically shaped tip. By way of anon-limiting example, using such a diverting tip, laser light emittedfrom a laser catheter having an approximate outer diameter of 1.4 mm andan approximate inner diameter of 1.14 mm may create an ablation havingan approximate diameter of 1.6 mm.

In some embodiments, the diverting tip 1650 may further include a hollowinterior, for example, to permit the passage of liquid and/or light fromthe inner lumen 1615 to pass through the diverting tip without diversionor deflection. In such embodiments, for example, the catheter 1600 mayormay not include an inner light guide 1630.

FIGS. 17A, B, and C show various examples of diverting tips 1650, 1651,and 1652 incorporated within the distal end of a laser catheter. In someembodiments, a diverting tip may include a cone with a linear taper. Asshown in FIG. 17A, cone shaped diverting tip 1650 may be placed withinthe distal tip of liquid laser catheter 1600. FIG. 17B shows acornshaped diverting tip 1651 with a convex taper that may be placed withinthe distal tip of a liquid laser catheter 1600. FIG. 16C shows funnelshaped diverting tip 1652 with a concave taper that may also be placedwithin the distal tip of a liquid laser catheter 1600. Diverting tips1650, 1651, and 1652 shown in FIGS. 17A, B, and C may come in any ofvarious other sizes and/or shapes. For example, in some embodiments, thecross section of a diverting tip may be round, oval or polygonal shaped.As shown in these figures, the taper may be linear, convex and/orconcave.

FIG. 18 shows laser catheter 1600 with a central optical fiber 1630 thatincludes a diverting tip 1650 coupled at the distal end according to oneembodiment. The diverting tip 1650 can be coupled with central opticalfiber 1630 using various methods including adhesives, mechanical holdingdevices, interference fit, etc. In other embodiment, diverting tip 1650is integral with central optical fiber 1630.

FIGS. 19A, B, and C show cross sections of the distal end of lasercatheters 1600 with various placements of diverting tip 1655 within thedistal end of laser catheter 1600, according to some embodiments. Whilethese embodiments show diverting tips coupled with central opticalfibers, however, such central optical fibers are not necessarily needed.As shown in FIG. 19A, distal end 1920 of diverting tip 1655 extendspartially past distal tip 1910 of laser catheter 1600. The diameter ofdistal end 1920 of diverting tip 1655 may vary to allow for a greater orsmaller gap 1930 between the distal tip 1655 and sheath 1610. Moreover,the position of the diverting tip 1655 may also be moved in order tochange the width of gap 1930.

FIG. 19B shows a sheath 1610 with a chamfer 1912, according to oneembodiment. Using chamfer 1912 may increase the width of gap 1930 and,therefore, provide a greater flow of liquid from catheter 1600 throughgap 1930. FIG. 19C shows a sheath 1610 with bend or kink 1914. Bend orkink 1914 may increase the width of gap 1930. Increasing the width ofgap 1910 may provide for increased liquid flow from catheter 1600. Suchan increase in the width of gap 1930, for example, may also change theflow of liquid from the catheter 1600. Moreover, the width, shape and/orangle of gap 1930 may provide a larger or smaller resulting spot size.

FIGS. 20A-E show various embodiments of diverting tips 2050, accordingto various embodiments. FIGS. 20A and 20B show solid diverting tips2050A and 2050B. Diverting tip 2050B shown in FIG. 20B has a moregradual taper 2055 than diverting tip 2050A shown in FIG. 20A. FIG. 20Cshows hollow diverting tip 2050C with aperture 2059 according to anotherembodiment. FIGS. 20D and 20E show convex tapered diverting tip 2050Dand concave tapered diverting tip 2050E respectively according tovarious embodiments. Concave and/or convex diverting tips 2050D and2050E may also be hollow and/or include a central aperture. Moreover,diverting tips 2050D and 2050E may not necessarily taper to a point asshown in FIGS. 20D and 20E. While FIGS. 20A-E show solid diverting tips2050, these diverting tips, for example, may also be hollow and/orinclude a channel through a central axis of the diverting tip 2050.

FIGS. 21A-C show various methods of attaching diverting tip 1650 tocentral optical fiber 1630. According to one embodiment, aperture 1659may have a portion of its surface raised 1660 and central optical fiber1630 may have a corresponding portion of its surface curved so that thetwo surfaces mate together when diverting tip 1650 is fitted withcentral optical fiber 1630. Likewise, aperture 1659 and central opticalfiber 1630 could be fitted with corresponding threads, 1664 and 1666respectively, so that diverting tip 1650 could be threadingly secured tocentral optical fiber 1630. Additionally, the inner diameter of aperture1659 could be sized slightly smaller than the outer diameter of centraloptical fiber 1630 so that an interference fit is provided betweenaperture 1659 and central optical fiber 1630. Alternatively, divertingtip 1650 could be constructed of heat shrink material so that, upon theaddition of heat, diverting tip 1650 shrinks onto the surface of centraloptical fiber 1630. Other methods of attaching diverting tip 1650 tocentral optical fiber 1630 could be employed such as using adhesive,detents, mechanical fasteners, etc.

FIG. 22 shows a diverting tip attachment 2220 coupled with a lasercatheter 2200 according to another embodiment. Diverting tip attachment2220 may be a removable distal tip that may be added or removed from thelaser catheter 2200. For example, diverting tip attachment 2220 may beremovably coupled with a standard laser catheter 2200. Thus, in use. forexample, a physician may add a diverting tip attachment 2220 to astandard laser catheter in order to increase the spot size of thecatheter. Diverting tip attachment 2220 includes a housing 2210 with adiverting tip 2250 coupled within. Diverting tip 2250 may be securedwithin diverting tip attachment 2220 using one or more attachmentmembers 2230. For example, attachment members 2230 may comprise a rigidmaterial. In other examples, attachment members 2230 may include string,wire or other material that couples diverting tip 2250 with divertingtip attachment 2200 and provide liquid flow therebetween. Diverting tip2250 shown in FIG. 22, in some embodiments may have a channel throughthe central axis of the diverting tip 2250. In yet other embodiments,diverting tip 2250 may be hollow.

FIGS. 23A and B show two different attachment mechanisms for divertingtip 2350 within a laser catheter and/or within a diverting tipattachment according to some embodiments. As shown in the figures, thediverting tip 2350 may be secured at the distal end of diverting tip2350 or along the tapered portion of diverting tip 2350 according tovarious embodiments. Various other attachment schemes may be employed.In some embodiments, diverting tip 2350 may be secured using variouswires and/or strings. In other embodiments, diverting tip 2350 may besecured in such a way to allow liquid to flow between the outer sheathand the diverting tip 2350. In some embodiments, for example, divertingtips 2350 may be hollow and/or include a channel through the centralaxis of the diverting tip 2350.

Specific details are given in the above description to provide athorough understanding of the embodiments. However, it is understoodthat the embodiments may be practiced without these specific details.For example, circuits, structures, and/or components may be shown inblock diagrams in order not to obscure the embodiments in unnecessarydetail. In other instances, well-known circuits, processes, algorithms,structures, components, and techniques may be shown without unnecessarydetail in order to avoid obscuring the embodiments.

While the principles of the disclosure have been described above inconnection with specific apparatuses and methods this description ismade only by way of example and not as limitation on the scope of thedisclosure.

What is claimed is:
 1. A catheter comprising: a sheath having a proximalend, a distal end, a liquid infusion port, and an inner lumen extendingfrom the liquid infusion port to the distal end of the sheath, whereinthe inner lumen is configured to receive fluid introduced into theliquid infusion port and, wherein the distal end of the sheath comprisesa completely solid tubular wall; a diverting tip positioned within theinner lumen, the diverting tip having a proximal end and a distal end,wherein the distal end of the diverting tip is larger than the proximalend of the diverting tip and is configured to divert at least a portionof fluid, wherein the diverting tip is configured to move relative tothe sheath; and a plurality of optical fibers having a distal end andconfigured to transmit light within the inner lumen of the sheath, theplurality of optical fibers positioned within the inner lumen of thesheath such that the distal end of the plurality of optical fibers isproximal to the diverting tip.
 2. The catheter of claim 1, wherein thediverting tip is hollow.
 3. The catheter of claim 1, wherein the sheathcomprises a tubular structure that surrounds the inner lumen, whereinthe tubular structure is constructed from a material configured toinduce reflection of light within the fluid.
 4. The catheter of claim 1,wherein the diverting tip is constructed from a material configured toinduce internal reflection of light within the fluid.
 5. The catheter ofclaim 1, wherein the diverting tip is further capable of permitting aportion of the light to exit the catheter tip without diverting thelight.
 6. The catheter of claim 1, wherein the deflecting member isconical in shape.
 7. The catheter of claim 1, wherein the diverting tipcreates a gap between the diverting tip and the sheath.
 8. The catheterof claim 7, wherein the gap is adjustable.
 9. The catheter of claim 7,wherein the diverting tip creates a proximal gap between the proximalend of the diverting tip and the sheath and a distal gap between thedistal end of the diverting tip and the sheath.
 10. The catheter ofclaim 9, wherein the proximal gap is greater than the distal gap.